Question: Khan.scratchpad.disable(); To move up to the maestro level in his piano school, William needs to master at least $157$ songs. William has already mastered $21$ songs. If William can master $10$ songs per month, what is the minimum number of months it will take him to move to the maestro level?
Solution: To solve this, let's set up an expression to show how many songs William will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since William Needs to have at least $157$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 157$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 157$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 10 + 21 \geq 157$ $ x \cdot 10 \geq 157 - 21 $ $ x \cdot 10 \geq 136 $ $x \geq \dfrac{136}{10} \approx 13.60$ Since we only care about whole months that William has spent working, we round $13.60$ up to $14$ William must work for at least 14 months.